diff --git a/src/interestCalculator.c b/src/interestCalculator.c
new file mode 100644
index 0000000..8acc998
--- /dev/null
+++ b/src/interestCalculator.c
@@ -0,0 +1,46 @@
+#include "interestCalculator.h"
+
+
+void calculateInterest(){
+float principalAmount;
+float interestPerYear;
+float timeInYears;
+
+printf("Please enter the principal amount:");
+scanf("%f",&principalAmount);
+
+printf("\nPlease enter interest per year (percentage):");
+scanf("%f",&interestPerYear);
+
+printf("\nPlease enter interest time in years:");
+scanf("%f",&timeInYears);
+
+float interestDecimal=interestPerYear/100;
+
+float result= principalAmount*(1+(interestDecimal*timeInYears));
+printf("\nAmount with the interest is %f.",result);
+}
+
+void initiateCalculator(){
+
+    int input;
+    printf("Welcome to the interest calculator. Please select an option:\n[1]Calculate yearly interest\n");
+    scanf("%d", &input);
+
+    switch(input){
+        case 1:
+        calculateInterest();
+        break;
+        default:
+        break;
+    }
+
+}
+
+/*
+int main(){
+
+    initiateCalculator();
+
+}
+*/
\ No newline at end of file
diff --git a/src/interestCalculator.h b/src/interestCalculator.h
new file mode 100644
index 0000000..bd641cd
--- /dev/null
+++ b/src/interestCalculator.h
@@ -0,0 +1,7 @@
+#ifndef INTERESTCALCULATOR_H_
+#define INTERESTCALCULATOR_H_
+
+#include <stdio.h>
+
+void calculateInterest();
+#endif
\ No newline at end of file